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LongTimeFordMan

Author Topic: BIG improvement in performance!  (Read 554 times)

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Offline fastfred

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BIG improvement in performance!
« on: May 16, 2018, 11:11:04 AM »
My car is powered by a 1977 2.4 Pinto motor. 3 speed auto.   It has the Holley twin choke carb. Several years ago I put the secondary main jet in the primary and with a jet drill opened the jet i put in the secondary choke. A decent improvement straight away.  Since then I have been shimming the linkage so that the secondary butterfly opens earlier.
 It is supposed to open when the primary opens when it is at 45 degrees.  I have it opening earlier and what a difference in pickup!  This happens from lows revs all the way through! At low throttle openings/cruising speeds the secondary is still closed but when I put my foot down the secondary kicks in and the car accelerates so much better.  This happens without the trans. changing from high gear. Big difference at even 2000 rpm in high gear. Probably uses more gas but the car is not my daily driver!

Fred

Offline Wittsend

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Re: BIG improvement in performance!
« Reply #1 on: May 17, 2018, 11:50:48 AM »
Might try advancing the ignition timing a little at a time too.  A lot of those cars had the timing retarded for smog reasons.  Maybe cam timing too. My daily drive is a 2000 Mazda Protege.  I advanced the ignition timing 4 degrees and the intake cam 3 degrees. It cost me nothing but my time and since I was replacing cam seals I was "in there" anyway.  All it took was filing (elongating) holes in the ignition reluctor and the cam pin hole.

While not the same method for your engine these mods made the car far "crisper" than it was before.